Sweat holds most promise for noninvasive testing -- ScienceDailyLast year the lab created the world's first continuous-monitoring sensor that can record the same health information in sweat that doctors for generations have examined in blood. The milestone is remarkable because the continuous sensor allows doctors to track health over time to see whether a patient is getting better or worse. And they can do so in a noninvasive way with a tiny patch applied to the skin that stimulates sweat for up to 24 hours at a time. "This is the Holy Grail. For the first time, we can show here's the blood data; here's the sweat data -- and they work beautifully together," Heikenfeld said. Heikenfeld and his students published their latest experimental findings in December in the journal Lab on a Chip. UC's study tracked how test subjects metabolized ethanol. The study concluded that sweat provided virtually the same information as blood to measure a drug's presence in the body.